Water motor



Aug. 18, 1931. c. P. HOWARD WATER MOTOR Filed March 5, 1931 2"Shee ts Sheet 1 277022 FEM/a3? Aug. 18, 1931 c. P. HOWARD WATER MOTOR I I Filed March 5, 1931 2 Sheets-Sheet 2 ////////II IIII4 Patented Aug. 18, 1931 UNITED STATES PATENT OFFICE CLIFTON P. HOWARD, F WORCESTER, MASSACHUSETTS, ASSIGNOR TO ROCKWOOD SPRINKLER COMPANY OF MASSACHUSETTS, A CORPORATION OF MASSACHUSETTS WATER MOTOR Application filed March 5,

This invention relates to a water motor capable of general application but particularly adapted for use in connection with the alarm mechanism of a dry pipe sprinklersystem. In such sprinkler systems, it is required that the alarm begin to sound as soon as water is admitted to the sprinkler pipes, which necessitates that the water motor which actuates the alarm mechanism shall begin to operate at a relatively low water pressure. It is also required that the alarm continue to operate as the pressure increases to full water main pressure.

It is the general object of my invention to provide a water. motor so designed and constructed that the motor will operate at a satisfactory speed at low pressure and will be selfretarding to prevent racing at high pressure.

A more specific feature of my invention relates to the provision of a special type of blade in a water motor or turbine, so designed that the lateral discharge of water from the blades will produce a choking effect which increases as the pressure of the water increases.

My invention further relates toarrangements and combinations of parts which will be hereinafter described and more particularly pointed out in the appended claims.

A preferred form of the invention is shown in the drawings, in which Fig. 1 is a partial sectional front elevation of an alarm mechanism having my improved water motor embodied therein;

Fig. 2 is a sectional side elevation of the water motor, taken along the line 22 in Fig. 1, and

Fig. 3 is a detail sectional view, taken along the line 3-3 in Fig. 2.

Referring to the drawings, I have shown an alarm mechanism comprising a rotor 10 mounted on a shaft 11 and connected to rotate a disc 12 having striker elements 13 adapted to engage the inside of a hell or gong 15 when the disc is rotated.

This general combination of water motor and striker mechanism is old and my present invention relates specifically to improvements in the water motor or turbine. These improvements, however, are particularly ap- 1931. Serial No. 520,338.

plicable and useful to the combination of mechanism shown in Fig. 1.

The water motor, as shown in the drawings, comprises a pear-shaped casing 20 in which the rotor 10 is rotatably mounted. Water enters the casing 20 through a nozzle 22 connected through a chamber 23 to a supply pipe'24. The pipe 24: is usually connected to the intermediate chamber of a dry pipe valve, which chamber is normally filled with air at atmospheric pressure.

When a sprinkler opens and the dry pipe valve operates, water is admitted to the intermediate chamber and flows through the pipe 24 to the nozzle 22. When first admitted, this water is at relatively low pressure but gradually builds up to full water main pressure as the system fills with water.

It is required that the rotor 10 commence to revolve as soon as water at low pressure enters the casing 20 through the nozzle 22. Consequently the parts are so proportioned that a et of water at relatively low pressure will cause rotation of the rotor 10 at sufficient speed to effectively strike the gong 15 and sound a satisfactory alarm.

As the pressure in the sprinkler system builds up, the pressure and speed of the jet through the'nozzle 22 similarly increases, causing a tendency on the part of the rotor to rapidly increase its speed or to race. Such high speed operation causes unnecessary wear on the bearings and other parts of the alarm mechanism and is generally undesirable.

In order to prevent such racing, I have provided the rotor '10 with blades 30 having the cross section shown in Fig. 3, with a rib or raised portion 32 at the center and with concave side portions 33 merging into a common transverse plane at the edges of the rotor.

The provision of blades having this novel cross section is found to produce a marked retarding effect upon the rotor as the pressure and speed of the jet increases. The water after striking the middle rib 32 is deflected sidewise against the adjacent inner walls oft-he casing 20, thus producing a turbulent or. choking effect which retards the rotor and prevents undue increase in the lUU speed thereof. This effect is increased by the provision of circumferential ribs 40 on the inside of the casing 20, extending under the rim 42 of the rotor and thus producing an annular chamber in which. the blades 30 rotate and in which the turbulent water is loosely confined.

A rotor thus constructed is found to rotate casil at a satisfactory speed under low pressure ut, as above described, the rotoris self retarding at higher pressures, thus greatly reducing the tendency to race and to cause undue wear of the parts.

The retarding effect may be further increased by providing a. somewhat restricted outlet opening 50 at the bottom ofthe casing 20 which. at high pressure, will cause the water to back up in the casing so that the lower portion of the rotor is submerged. The opening 50 is made of such size, however, that the backing up of the water will not reach the point Where the bearings are submerged, thus avoiding the possibility of leakage through the bearings, an objection previously encountered.

It will be noted that the blades 30, while having relatively straight or flat edge portions in a transverse plane, are nevertheless concaved forward ina plane perpendicular to'the axis of rotation, thus producing a semieupped effect to increase the propelling action of the jet but discharging the water laterally instead of throwing it forward as in the usual commercial type of rotor blade.

Having'thus described my invention and the advantages thereof, I do not wish to be limited to the details herein disclosed, otherwise than as set forth in the claims, but what I claim is I j 1. In a water motor having a casing and means to direct a jet of liquid therein, a rotor mounted in said casing and having a plurality of blades movable in the path of said jet, and each blade having a forwardly projecting middle rib and rearwardly sloping side surfaces, whereby said blade is self-retarding under increased jet speed.

2. In a water motor having a casing and means todirect a jet of liquid therein, a rotor mounted in said casing and having a plurality of blades movable in the path of said jet, and each blade having a forwardly projecting middle rib and rearwardly sloping concave side surfaces, whereby said blade is self-retarding under increased jet speed.

3. In a water motor having a casing and means to direct ajet of liquid therein, a

rotor mounted in said casing and having a plurality of blades movable in the path of said jet, each blade having a forwardly projecting middle rib and rea-rwardly sloping side surfaces, whereby said blade is self-retarding under increased jet speed, and the portions of said surfaces adjacent the edges of said blades being substantially perpendicular to the plane of rotation of said rotor.

4. In a water motor having a casing and means to direct a jet of liquid therein, a rotor mounted in said casing and having a plurality of blades movable in the path of said jet, each blade having a forwardly projecting middle rib and rearwardly sloping side surfaces, whereby said blade is selfretarding under increased jet speed, and said blades being rearward'ly concave in the plane of rotation of said rotor.

5. In a water motor having a casing and means to direct a jet of liquid therein, a rotor mounted in said casing and having a plurality of blades movable in the path of said jet, each blade having a forwardly projecting middle riband rearwardly sloping side surfaces, whereby said blade is self-retarding under increased jet speed, and said casing having inwardly projecting annular ribs adjacent the blade-supporting portion of the rotor, whereby an annular chamber is provided for said blades.

6. In a water motor having a casing and means to direct ajet of liquid therein, a rotor mounted in said casing and having a plurality of blades movable in the path of said jet, each blade having a forwardly projecting middle rib and rearwardly sloping side surfaces, whereby said blade is self-retarding under increased jet speed, and said casing having a restricted outlet whereby a further retarding effect is vproduced.

7. In a water motor having a casing and means to direct a jet of liquid therein, a rotor mounted in said casing and having a plurality of blades movable in the path of said jet, each blade having a forwardly projecting middle rib and rearwardl y sloping side surfaces, whereby said blade is self-retarding under increased jet speed, said casing having a discharge outlet restricted to produce a further retarding effect but of sufficient size to prevent flooding of the bearings.

In testimony whereof I have hereunto affixed my signature.-

CLIFTON P. HOWARD, 

